   (defn degrandis-pets [t-map data-point opt-map]
     (and (= (get-in t-map [:name :last]) "deGrandis")
          (:has-pet t-map)
-         {}))
+         nil))
 
   (def valid-paul [[[:name :first] [(fn [t-map data-point opt-map] (and (= data-point "Paul")
                                                                         {:a 1 :b 2}))]]

  (def paul-rules (query/normalize valid-paul))
  (validation-seq paul paul-rules)
  (validation paul paul-rules)
  (validation paul paul-rules identity)

)



(defn validation
  "Validate a data structure, `t`,
  against a normalized validation query/rule-set
  Note: By default everything is returned in a map, keyed by
  the coordinate vector.  It is possible for validation results to be
  stomped on."
  ([t normalized-query]
   ;; For some reason `doall` doesn't work here
   (apply hash-map (into [] (mapcat identity (validation-seq t normalized-query)))))
